LeagueInsights Connector

Loads your own Yahoo Fantasy league data for LeagueInsights from this browser, so your Yahoo login never leaves your computer.

LeagueInsights (https://www.leagueinsights.app) adds standings, draft analysis, keeper tracking, playoff odds and a live draft lottery to a Yahoo Fantasy league. This extension is the part that loads your league. Yahoo restricted its public Fantasy API in 2026, so LeagueInsights can no longer read your league from its own servers. Instead, this extension reads it from the browser you are already signed in to Yahoo with, and sends the league data — standings, rosters, transactions, draft results — to your LeagueInsights account. WHAT IT DOES • When the LeagueInsights web app needs your league data, the extension fetches it from Yahoo's read-only fantasy API in this browser and passes the result to your LeagueInsights account. • When you are browsing your own league on Yahoo, the extension tells LeagueInsights which league you are looking at, so your data can be refreshed while your Yahoo session is known to be working. It sends the sport and the league number, and nothing from the page. • The commissioner of a league can upload a generated schedule back to Yahoo. This is the only action that changes anything on Yahoo, it happens only when the commissioner asks for it in the app, and it can only reach the league's own schedule form. WHAT IT DOES NOT DO • It does not read, store or transmit your Yahoo password, cookies or any other credential. It has no access to your cookies at all — the browser attaches your Yahoo session to its own requests, which is why the extension never needs to see it. • It cannot touch Yahoo Mail, your Yahoo account settings, or any Yahoo site other than fantasysports.yahoo.com. This is enforced twice: the extension requests access to no other Yahoo host, and it checks every request against its own built-in list of permitted addresses before performing it. • It does not read, inject into or observe any third-party website. Its only content script runs on leagueinsights.app, where it does one thing: tell the page that the extension is installed. • It shows no ads, sells no data, and uses your browser for nothing except your own league. TRANSPARENCY Click the toolbar icon to see exactly what the extension has done: how much data it has loaded, when it last checked in, and the last eight requests with their result. Those counters are computed and kept in this browser, and are never uploaded. SETUP 1. Create an account at https://www.leagueinsights.app and sign in. 2. Open Settings → Yahoo Sync and copy the pairing code shown there. 3. Click this extension's icon, paste the code, and press "Link account". Requires a LeagueInsights account and a Yahoo Fantasy league. Not affiliated with, endorsed by, or sponsored by Yahoo. Yahoo and Yahoo Fantasy are trademarks of their respective owner.